Film drying machine



Ha N. ENslGN ET AL 2,096,232

FILM DRYING MACHINE Original Filed March 13. 1935 2 Sheets-Sheet l Even/*0r* .J1/2117115. JK' EnszQn/ Jfarryy ..7[a2250/7/- Oct. 19, 1937.

H. N. ENslGN E -r AL FILM DRYING MACHINE original Filed March 13,A 1955 2 Sheets-Sheet 2 i ztmlmw War/2 Q Patented ocr. 19, 1937 2,096,232 FILM name MACHINE Harris N. Ensign. Los Angeles,v and Harry A. llanson, Weet-Loo Angeles, Calif., assis-nora to Paramount Productions, Inc., Los Angeles, Calif., a corporation of Delaware v Application March 13.193,5. Serial No. 10,841 Renewed May 3, 1937 2Claiml.

'Ihis invention relates generally to drying machines for motion picture film, and more particularly to machines for drying a continuously mov- Lug film strip supplied continuously from a wet ath.

The drying machine disclosed and claimed in the present application is also disclosed, and in some aspects claimed, in our copending application entitled Horizontal type nlm developing and drying machine, led March 13, 1935, Ser. No. 10,840.

It may be stated as an object of the present invention to provide a film drying machine which is highly eicient and exceptionally rapid in drying the lm.

It is a further object of the invention to provide a film drier with improved film driving and carrying means, designed with the view of equalizing lm tension throughout the machine.

It is believed the invention itself, as well asV additional objects not specifically named, will be most easily understood by proceeding at once to a detailed description of a present preferred embodiment of the invention, reference for this purpose being had to the accompanying drawings, in which:

Fig. 1 is a side elevation of the ilm drying machine of the invention;

Fig. 2 is a longitudinal vertical medial section of the iirstsection of the drier;

Fig. 3 is a plan view of the last section of the drier, the upper wall being broken away;

F ig. 4 is a vertical section taken on line 4-4 of Fig. 3;

Fig. 5 is a section taken on line 5-5 of Fig. 3;

Fig. 6 is a section taken on line 6-6 of Fig. 3;

Fig. 7 is a detail section taken on line 1-1 of Fig. 4:

Fig. 8 is a section taken as indicated by line 8-8 of Fig. l.

The drier is shown to embody a long, closed conduit I0, preferably rectangular in cross section, and is here illustrated as mounted on supports II. Said conduit is made up of top and bottom walls I3 and I4, respectively, and side walls I5. The side walls may have suitable doors not shown, for the purpose of gaining access to the'interior of the drier.

The drier is divided into a number of successive film-carryingl sections, such as A, B, C and D, section A being shown in vertical longitudinal section in Fig. 2, and section D being shown in Figs. 3 and fl.

Each of such drier sections comprises a pair of longitudinally spaced lm roller shafts 2| and 22, and midway between said shafts, and preferably on the same level, a third shaft 24. Freely and rotatably mounted on the end shafts 2l and 22 are individual fllm rollers 20 (see Fig. 5) and nonrotatably mounted on center shaft 24 is a film-driving drum 25, which in the present illustrative embodiment is of a diameter substantially six times that of the lm rollers on end shafts 2| and 22. The diameter of this drum is vof course susceptible to considerable variation, the diameter indicated not being limitative on the invention in its broader aspects.

As is shown in Figs. 3 and 6, drum 25 is made up of end plates 21 rigidly mounted on shaft 24, and a drum cylinder 29 mounted at its two ends on annular anges 30 extending inwardly from plates 21. Preferably, a fabric covering 3| is stretched over the exterior of the cylinder 29, and is fastened tightly in place between the ends of the cylinder and the previously mentioned flanges 30, as clearly shown in Fig. 6. The fabric covering is of a nature suitable to give a frictional driving engagement with the drying film strip.

Drum shaft 24 has on its outer end, outside side wall I5, a wheel 35 which is drivingly engaged on its top side by friction wheel 36 mounted on the end of a spindle 31 journaled in a turbine wheel mounting box 38, the latter being secured to the side of the drier as indicated in Fig. 6. Friction wheel 36 is preferably formed of cork, which is found to have great durability, as well as to permit slippage should the turbine be too strongly driven. On the other end of shaft 31 is a gear 40 engaged by a gear 4I mounted on turbine wheel shaft 42. Shaft 42 has on its outer end an air turbine wheel 43 provided with blades 44. The turbine wheel is driven from air discharged by nozzle 45 which is positioned to direct air current against blades 44, the air being controlled by a hand valve 41 in supply pipe 48. The turbine wheel is enclosed by a casing 49, as indicated.

The film strip F, which may be understood as supplied continuously from the wet bath, not shown, is here illustrated as enteringthe drier conduit through an aperture I6 in its lower wall I4, said aperture being located near the right hand end of the conduit as viewed in Figs. 1 and 2. 'Ihe lm upon entering the drier conduit passes upwardlyand around end film roller 20 on transverse shaft 2I of drier section A, thence traverses sections A, B, C and D in succession. As clearly indicated in the drawings, the film entering oneof the sections passes over the top side of the iilm driving drum 25, thence passes downwardly at a small angle and loops around I passes under the lower side of drum 2i 'and so back to a roller 2l on shaft 2l. looking upwardly around said roller and paling forwardly again over the top side of drum 2l, and so on in successive convolutions to the other side ofthe conduit. ,After thus traverdng a' given drier section, the nlm from the top side of the center driving drum goes forwardly to the center driv-V ing drum of the next section, as indicated.

nahen mbe noted tnattnemmmip mustbe threaded on the sets of rollerson the several drier sections with its emulsion side out. 'mis is of great importance, nrst, in that the emulsion is mutilated if the emulsion side of the nlm is ailowed to come into contact with the surface of the rollers, and second, in that it is highly desirable thatthe emulsion side of the nlm be on the outer side of the nlm convolutions where the drying effect of the heated air stream .is much the greater.

In lthe particular design here shown the in'-l dividual nlm rollers 20 on the two end shafts 2i and 22 of each drier section are mounted directly opposite one another, rather than being staggered, and the nlm strip is carried straight forwardly from the top sides of the rollers on shaft 2| to the ton sides of the rollers on shaft 22, and is angled in running from the lower sides of the rollers on shaft 22 to the lower sides of the rollers on shaft 2l (see Fig. 3). It is found that the angularv stretches of the nlm strip tend to work laterally a fraction of an inch on ythe nlm driving drum during operation, so that the edge of the nlm strip rubs against any usual nlm guide means that might be provided adjacentv the driving drum, such for instance as flanges on the wheel itself, or guide rollers, or wire loops mounted adjacent said drum. Accordingly, we provide a nlm guide means directly before the driving drum which is freely shiftable in a lateral direction to accommodate this tendency oi'. the nlm to work over slightly on the drum. As shown in Figs. 4 and l'7, there is provided just before the driving drum a bar having individual nlm guides in the form of wire loops Il which are adapted to take and space the successive stretches of the nlm strip passing under vthe drum.

This bar extends transversely of the conduit and its two ends are notched at 54 and are slldably mounted on guide pins 56, as clearly indicated in the figure. It will be evident that the guide bar therefore noats laterally, and accommodates its position to that naturally taken by the nlm on the driving wheel.

Preferably, sets of nxed nlm guide loops Il and 59 are mounted just before the rollers on shafts 20 and 2|, respectively, as clearly indicated in Figs. 3 and 4.

Polishing rollers 51, covered with chamois or other suitable surface material, are preferably mounted between thenlm rollers and center driving drum in drier section A, as clearly indicated in Fig. 2, and serve to polish the celluloid surface of the nlm passing between the nlm rollers and the center driving drum. i

From end drier section D, the nlm passes between a pair of ejector rollers Il and Il (Fig. 4) and passes outside the drier conduit by way of a comparatively narrow slot il to be reeled up on take-up reel I2. Roller 8l is constantly. driven through the medium of a pulley It and belt l1 driven by a pulley il. which is rotatably mounted on a spindle 69 that supports nlm roller shaft 22 (Fig. 5). Integral with pulley l is pulley Il drivenby abeltli whichisdrivenin-turnbya pulley 'I2 fastened to the end ofnlm driving drum 2l. The other nlm ejector roller into engagement with the nlm `by a spring,l 1I (Fig. 4) Elector roller l. is driven ata speed suchasto takethe nimjust'as itissuppliedfrom drier''section D.

'me mm nim take-wt dem u designated at ,8I(I'igs.1and8),andcomprisessreelshsftll,

carrying take-up reel l2, and having rigidly' by air from a nozzle 80. The air from this nozzle is adjusted by hand valve Il to give the turbine just sufficient drive that the .reel l2 on shaft Il will beslightly overdriven, that i s will exert a slight tension on the nlm coming from the ejectoi of the drier.

It will be understood that the drier receives the nlm immediately from a wet bath machine of some description which in operation will supply the nlm strip at some given rate. The drier turbines are adjusted so that the rotating nlm driving drums 24, which are in frictional engagement with the sets of nlm convolutions in the drier, have a slight tendency to over-drive the nlm through the drier, and therefore to exert a slight tensing on the nlm coming from the wet bath machine. This over-drive, of course, is not sufficient to strain the nlm, but is only sunicient to maintain a suitable tension in the nlm and to take the nlm at whatever rate it may arrive from the wet bath machine. Accordingly, when the machine is in full operation, the air turbine wheels are held back slightly by the nlm strip.

Inssmuch as each nlm driving drum is in driv'- ing engagement with a number of nlm-convolutions, the tension exerted in each run of the nlm due to this over-drive tendency is very small, and the nnal result is to give a very gentle driving effect at each point of contact between the driving drum and the i'llm strip.

The nlm ejector at 60, 6I and the nnal takeout device 00 then remove the nlm from the drier and reel it up, the take-outdevice also being adjusted with a slight over-drive tendency so as to draw the nlm from the drier and prevent slack is in practice imposed by the we machine that supplies the nlm to the drier at some given rate. It will be sufficient for the present purpose merely to consider that the nlm is to be fed to the drier at substantially a constant rate of speed, thereby permitting the air turbines to be adjusted to sive just the slight necessary over-drive tendency required to maintain proper tension in the nlm strip for that rate of nlm feed. Any slack which then comes into the nlm due to wetting and elongation occurring in the wet bath will be taken up by the over-drive tendency of the drier and its overdrive take-out, andthe slack accordingly moved forwardly through the drier to be taken up nnslly through outlet air conduit 9|.

by the over-driven take-up reel. Of course, the greater part of such slack is taken up by natural nlm shrinkage as moisture is removed from the nlm within the drier, but any excess slack is constantly moved forwardly through the machine and is taken up by the final take-out device. As a result, the nlm strip in the drier is maintained with a proper tension to give required driving engagement between the driving drum and the nlm, regardless of changes in nlm length due to elongation inthe preceding wet bath, or shrinkage in the drier.

'Ihe nlm roller and driving drum arrangement of the drier is designed with the particular view of equallzing tension between the various film convolutions. It is for this purpose that the nlm rollers 20 on the end shafts 2| and 22 kof each drier section are mounted for free individual rotation. It will be evident that this individual freedom of rotation of each of said rollers allows the nlm strip to work in such a way as to equalize the tension throughout all its convolutions. The nlm strip of course must slip somewhat on the surface of the central driving drum as it is tensed up, or during movement of slack through the machine, but the individual rotatability of each of the nlm rollers allows the nlm strip to work through each of the several sections of the drier with such freedom, even with any such slip on the central drum, that tension in the nlm always is equalized in the convolutions of each drier section. The nlm convolutions therefore maintain a very accurate balance of tension between themselves, and the driving tendency of the central driving drum is held exactly the same on all nlm convolutions.

It has been described how the nlm is polished by the polishing rollers 51. The nlm is also polished in slipping slightly on the central driving drums 25. It will be evident that such slippage will depend upon the tension placed on the nlm, which may be controlled by regulating the hold-back on the nlm at the beginning end of drier, or by regulating the force exerted by the nnal take-out device.

A current of heated air is delivered to the nlm outlet end of the conduit through an air inlet conduit 90. This current ofheated air passes over the successive sections of the drier comprised of several sets of longitudinally arranged nlm convolutions, and is nnally discharged It will be noted that the air blast is thus in a direction contrary to the direction of nlm progression through the conduit. Accordingly, the heated air upon introduction to the conduit comes first into contact with that portion of the nlm which has longest been in the drier conduit and is consequently already substantially "dry, and then passes on through the successive sections of the drier wherein the nlm is in progressively wetter condition.` 'Ihe air of course becomes more and more laden with moisture as it passes from section to section, with the result that its drying effect is lessened as it passes through the conduit. The nlm in the last nlm section D, however, is always subjected to the innuence of the dry incoming air. This arrangement is conducive to most effective and rapid drying of thenlm.

It is to be noted that the sets of parallel, elongated nlm convolutions of the drier are arranged longitudinally of the heated-air conduit. or in other words, parallel to the direction of heated air now. It will also be remembered that the nlm strip passes over the successive sets of nlm convolutions emulsion side out. These features of design and arrangement are productive of greatly increased efficiency of drying, as may be appreciated from the considerations following. It is of course well known that it is the emulsion face of the celluloid nlm strip that requires time for drying, the emulsion being in a very sticky and plastic state when wetand requiring a much longer time to dry than does the celluloid. In our drier design, the nlm strip is arranged throughout the sets of elongated convolutions in each of the successive drier sections with its emulsion side out, that is, presented to the heated air stream that is continuously passed through the drierconduit. Within the nlm convolutions, the air is relatively quiet, and drying would be relatively slow and ineffective; however, `as has been said, the celluloid drys rapidly, and the inner side of the nlm strip vnevertheless is completely dry before the nlm leaves the drier. Outside and along the outer sticky surfaces of the longitudinal runs of the nlm convolutions, the heated air stream nows rapidly along in a continuous stream, licking the emulsion surfaces of the nlm strands and rapidly removing the moisture therefrom as it passes. This air stream is not broken up and caused to now in various cross and counter directions, but is always substantially parallel to the longitudinal runs of the nlm in the conduit; moreover, very nearly one hundred percent of the nlm within the convolutions of the drier runs in a longitudinal direction, parallel with the air stream and with its emulsion surface presented thereto in the most effective manner for rapid drying. As a result of the features here spoken of, the drying time is reduced very materially below what is usual in prior driers of standard types, and consequently the total nlm footage required within the drier, and therefore the size of the drier itself, are correspondingly reduced. As an example, we may state that a present drier constructed as here described has a total capacity of but 12,000 feet of nlm, and the nlm is comple'tely dried when running at a speed of 130 feet per minute with air blown through the conduit at a temperature of but F. In comparison with this performance, a nlm drier of a standard commercial type now in continuous use under our supervision carries a length of 26,000 feet of nlm, and operates at a speed of feet per minute using air heated to 100 F. The reduction in necessary size of apparatus, in footage of nlm at any one time in the drier, and the increase in speed through the drier, together with the necessity of'heatlng the drying air to but 85 F., all of which constitute features of greatest advantage, will be'readily apparent from these comparative figures.

It will be understood the drawings and description are to be considered as illustrative of and not restrictive on the broader claims appended hereto, for various changes in design, structure and arrangement may be made without departing from the spirit and scope of said claims.

We claim:

1. In a nlm drier, the'combination of an air conduit adapted to have a blast of air forced therethrough, and a plurality of nlm carrying units within said air conduit and spaced longitudinally thereof, said units being adapted to take the nlm successively and pass it from unit to unit in a direction contrary to the direction of the air blast, each of said units comprising two sets ofnlm rollers mounted on parallel horizonm ma .pme mnatudmul'y of the comme .ma`

errangedeothetthenlmstripgmeybelooped therearound in edjncent convolution: which ex. tend longitudinally oi' the. conduit. end e rotetableilixndrivingwheelo!edimlnetergreetertimny thotot the nlm rollers extending through seid nlm eonvolutione. with its exis ofnotetion pernileitoendbetweentheexeeotsnideetsotiiim rollers. seid driving wheel being errenged for frictionel driving engagement with the nlm moving in both directions between seid eets of rollers.

2.1n nillm drier, the oombinntion'o! en nir conduit ndnpted to have n blast of nir forced therethrough. and nlm carrying menne comprising two sets oi iilm rollers mountedon parallel horisontel exeespeoedlongltudinelly ofthe oonduitenderrengedeothetthemmstripmeybe thereeround in. edieoent convolutions which extend longitudinallyv o! the conduit. ond eroteteblenixndrivingwheeloiediemeter greater then thet o! the nlm rollers extending throughidnlm convoiutlone..with itsnxis oi' rotation perellel to and between the exee ot seid sets ofrillm rollers. sniddriving wheel being erranged for trlctionel driving engagement with the nlm moving in both directions sets o! rollers. Y

HAR-RIB N. ENSIGN. HARRY A. HANSON. 

